Gas infra-red radiant tube heaters are well known in the art. The basic concept involves a gas heater which uses a forced mixture of a combustible gas, such as natural gas, and air flowing within a radiant tube over an ignition element to ignite and burn the mixture. This burning causes the tube to heat up and radiate the heat therefrom. Typically within the heater assembly are various switches, valves and other components which operate the system in both the normal operating mode and in safety shutdown modes. These components are heat sensitive and cannot withstand the heat of the combustion. Therefore, should the flame created by the element burn back into the location of the components, they can be severely damaged. Consequently, the need to prevent this damage to the components due to burn-back is a great concern.
For radiant tube heaters in general, four different operating conditions or environments exist. First, the heater may be designed to operate within the residential indoor environment, in which case the exhaust from the heater needs to be vented directly into a flue leading to the outside of the building. Typically, this unit also needs a compact, self-contained unit that can safely mount close to walls or ceilings since space is generally limited. Second, the heater may be designed to operate within the industrial environment. In this case, the exhaust from the heater needs to be operated within a certain type of vented building or vented directly into a flue leading to the outside of the building. Third, it may be designed to operate within the outdoor environment. In this case, it needs to be sealed against moisture, such as rain, to avoid interference with and damage to the heater's interior components. It also needs to be made of a material that resists corrosion. Finally, the heater may be designed to operate within a living area for livestock production, such as raising chickens or pigs in which case, again, the need to be able to vent to the outside of a building. Many of the typical radiant tube heaters cannot be used under all four of these conditions, thus requiring different designs and configurations of heaters for each of these applications.
Furthermore, many of the typical radiant tube heaters are not enclosed within one complete, compact unit which can be quickly and easily installed to operate safely in any one of the four operating conditions. This need can be met by a compact enclosed sealed unit that can safely and easily mount close to building walls or ceilings, can hang at several different angles from horizontal to radiate the heat where it is needed, and can quickly and easily connect to a flue for venting the exhaust directly to the outside of the building.
Additionally, in order to service many typical radiant tube heaters, individual components need to be analyzed for damage or defect and repaired on location. This is not as convenient as quickly and simply replacing a single modular unit within the heater that contains all of the serviceable parts and can be sent back to the manufacturer for factory service at a later time.